1. Technical Field
The invention relates to a well completion process and more particularly to a well completion process wherein the well penetrates a subterranean hydrocarbon-bearing formation.
2. Description of Related Art
Well completion is a comprehensive term encompassing a number of operations performed in a hydrocarbon wellbore, after drilling part or all of the wellbore, but before the well is put into service as a production or injection well. A common well completion operation is to place a metal casing in a newly drilled wellbore and set the casing with cement to, inter alia, prevent the unwanted production of hydrocarbon gases, hydrocarbon liquids, and/or other fluids from specific intervals of the wellbore.
Horizontal drilling in a hydrocarbon-bearing formation produces a wellbore which cannot be completed by conventional methods. Horizontal wellbores are generally drilled horizontally to follow a hydrocarbon-bearing zone and improve production therefrom. The horizontal wellbore may be formed by drilling horizontally away from a substantially vertical wellbore at a predetermined depth in the vertical wellbore which corresponds to the approximate depth of the producing zone. The horizontal wellbore is initiated or "kicked off" from the vertical wellbore by a radius. A horizontal wellbore may alternatively be initiated at the surface by drilling a radius directly from the surface until a predetermined depth corresponding to the depth of the hydrocarbon-bearing zone is reached. Thereafter, the wellbore is drilled horizontally through the producing zone. In either case, the radius is defined as a relatively short section of sharply curved, nonlinear wellbore which provides a transition from a vertical wellbore or the surface to a horizontal wellbore. The radius is necessitated because it is operationally impractical to initiate a sharp right angle bore hole in the face of a vertical wellbore.
It is difficult, if not impossible, to set casing in the radius and horizontal wellbore because of the sharp curvature in the nonlinear path of the radius and the relative inflexibility of the metal casing tubulars. Thus, the radius and horizontal wellbore are often maintained as uncased open holes, into which unwanted fluids are free to migrate from the surrounding rock.
A well completion process is needed which seals an uncased open wellbore to prevent the migration of unwanted fluids into the wellbore. A well completion process is needed which inexpensively and effectively seals a radius or horizontal wellbore deviating downhole from a vertical wellbore.